| Title | Diamondiferous Paleoproterozoic mantle roots beneath Arctic Canada: a study of mantle xenoliths from Parry Peninsula and Central Victoria Island |
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| Author | Liu, J G ; Brin, L
E; Pearson, D G; Bretschneider, L; Luguet, A; van Acken, D; Kjarsgaard, B; Riches, A; Miskovic, A |
| Source | Geochimica et Cosmochimica Acta vol. 239, 2018 p. 284-311, https://doi.org/10.1016/j.gca.2018.08.010  Open Access |
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| Year | 2018 |
| Alt Series | Natural Resources Canada, Contribution Series 20200196 |
| Publisher | Pergamon-Elsevier Science Ltd |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Northwest Territories |
| Area | Perry Peninsula; Central Victoria Island |
| Subjects | geochemistry; Nature and Environment; Science and Technology; mantle; diamond; osmium; isotopes; elements; craton; Proterozoic |
| Illustrations | location maps; figures; composite sections; plots; tables; histograms |
| Released | 2018 08 13 |
| Abstract | While the mantle roots directly beneath Archean cratons have been relatively well studied because of their economic importance, much less is known about the genesis, age, composition and thickness of
the mantle lithosphere beneath the regions that surround the cratons. Despite this knowledge gap, it is fundamentally important to establish the nature of relationships between this circum-cratonic mantle and that beneath the cratons, including the
diamond potential of circum-cratonic regions. Here we present mineral and bulk elemental and isotopic compositions for kimberlite-borne mantle xenoliths from the Parry Peninsula and Central Victoria Island, Arctic Canada. These xenoliths provide key
windows into the lithospheric mantle underpinning regions to the North and Northwest of the Archean Slave craton, where the presence of cratonic material has been proposed. The mantle xenolith data are supplemented by mineral concentrate data
obtained during diamond exploration. The mineral and whole rock chemistry of peridotites from both localities is indistinguishable from that of typical cratonic mantle lithosphere. The cool mantle paleogeotherms defined by mineral thermobarometry
reveal that the lithospheric mantle beneath the Parry Peninsula and Central Victoria Island terranes extended well into the diamond stability field at the time of kimberlite eruption, and this is consistent with the recovery of diamonds from both
kimberlite fields. Bulk xenolith Se and Te contents, and highly siderophile element (including Os, Ir, Pt, Pd and Re) abundance systematics, plus corresponding depletion ages derived from Re-Os isotope data suggest that the mantle beneath these parts
of Arctic Canada formed in the Paleoproterozoic Era, at similar to 2 Ga, rather than in the Archean. The presence of a diamondiferous Paleoproterozoic mantle root is part of the growing body of global evidence for diamond generation in mantle roots
that stabilized well after the Archean. In the context of regional tectonics, we interpret the highly depleted mantle compositions beneath both studied regions as formed by mantle melting associated with hydrous metasomatism in the major
Paleoproterozoic Wopmay-Great Bear-Hottah arc systems. These similar to 2 Ga arc systems were subsequently accreted along the margin of the Slave craton to form a craton-like thick lithosphere with diamond potential thereby demonstrating the
importance of subduction accretion in building up Earth's long-lived continental terranes. |
| GEOSCAN ID | 326608 |
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